Britain’s Ministry of Defense has described the Wagner mercenary group’s armed rebellion as the most significant challenge to the Russian state in recent times. The ministry’s intelligence update posted Saturday says that the feud between Yevgeny Prigozhin’s group and the Russian state has “escalated into outright military confrontation.” It says there is very limited evidence of fighting between Wagner and Russian security forces. The statement said that “over the coming hours, the loyalty of Russia’s security forces, and especially the Russian National Guard, will be key to how the crisis plays out.”